1. Technical Field
The invention relates to the setup and maintenance of computer networks in a computer environment. More particularly, the invention relates to the automatic setup of virtual networks and adaptive reconfiguration of network topology in a computer environment.
2. Description of the Prior Art
Virtual networks are created over the existing network topology. The connectivity of the network is taken advantage of by creating an efficient routing system through the network, i.e. a virtual network. When setting up a virtual network, it is necessary to configure the virtual routers to talk to each other.
One common approach is to statically configure which virtual routers will talk to other routers. The system administrator manually enters the network connections into each router. The network configuration does not change until the system administrator manually changes it. This requires maintenance and redundant links to get reliability because if one router goes down, messages cannot get through until that router comes back up.
Referring to FIG. 1, a network backbone 101 has been established in a local network and new users 102, 103 want to connect onto the backbone. The new users 102, 103 may have to connect through the Wide Area Network (WAN) link 105 to get to the backbone, which is much more expensive. If a new virtual router 104 is later added to the local network 101, then it would be more economical for the users 102, 103 to connect through the local router 104 rather than through the WAN 105. However, in a static configuration, the system administrator must tell each of the users 102, 103 of the existence of the new router 104 and have them reconfigure their machines.
Another approach is to do away with the virtual multicast system and run directly over the Internet Protocol (IP) multicast system. The drawback is that IP multicast is not flexible enough to perform the filtering that is needed. With respect to FIG. 2, a multicast application 201 has two sets of users 202, 203 that are not interested in each other's traffic. In an IP multicast system, either two multicast addresses would be needed which would be difficult to get authoritatively, or all of the users would simply receive everyone else's traffic.
It would be advantageous to provide a virtual routing system that automatically sets up the virtual network topology. It would further be advantageous to provide a virtual routing system that adapts to changes in the network connectivity by automatically reconfiguring the virtual network topology.